Plant response to changes in environment is complex and interlinked with hormone homeostasis that drive several adaptive responses. Rice varieties that express the SUB1A-1 allele (referred to herein as SUB1A) are tolerant to submergence whereas varieties lacking SUB1A are not. SUB1A exerts is effect by preventing shoot elongation, reducing carbohydrate consumption, preventing chlorophyll breakdown and activating alternative energy pathways. SUB1A has also been reported to promote plants survival during drought stress conditions (Fukao et al., Plant Cell 23:412-427, 2011).
SUB1A interacts with various proteins, including SAB18 (Seo et al., PLoS Genetics 7:1-12, 2011). SAB18 is a trihelix protein. Sequence analysis indicates the present of a Myb/SANT-like DNA-binding domain, which has been shown to be involved in carbohydrate and nucleotide metabolism. SAB18 has also been postulated as being involved in tolerance to submergence (Seo et al., PLoS Genetics 7:1-12, 2011) as a negative regulator. However, the role of SAB18 in conferring tolerance to submergence or drought tolerance has not previously been demonstrated.